@article{vanKleunenFischer2005, author = {van Kleunen, Mark and Fischer, Markus}, title = {Constraints on the evolution of adaptive phenotypic plasticity in plants}, year = {2005}, abstract = {The high potential fitness benefit of phenotypic plasticity tempts us to expect phenotypic plasticity as a frequent adaptation to environmental heterogeneity. Examples of proven adaptive plasticity in plants, however, are scarce and most plastic responses actually may be 'passive' rather than adaptive. This suggests that frequently requirements for the evolution of adaptive plasticity are not met or that such evolution is impeded by constraints. Here we outline requirements and potential constraints for the evolution of adaptive phenotypic plasticity, identify open questions, and propose new research approaches. Important open questions concern the genetic background of plasticity, genetic variation in plasticity, selection for plasticity in natural habitats, and the nature and occurrence of costs and limits of plasticity. Especially promising tools to address these questions are selection gradient analysis, meta-analysis of studies on genotype-by-environment interactions, QTL analysis, cDNA-microarray scanning and quantitative PCR to quantify gene expression, and two-dimensional gel electrophoresis to quantify protein expression. Studying plasticity along the pathway from gene expression to the phenotype and its relationship with fitness will help us to better understand why adaptive plasticity is not more universal, and to more realistically predict the evolution of plastic responses to environmental change}, language = {en} } @article{EsslDawsonKreftetal.2019, author = {Essl, Franz and Dawson, Wayne and Kreft, Holger and Pergl, Jan and Pysek, Petr and van Kleunen, Mark and Weigelt, Patrick and Mang, Thomas and Dullinger, Stefan and Lenzner, Bernd and Moser, Dietmar and Maurel, Noelie and Seebens, Hanno and Stein, Anke and Weber, Ewald and Chatelain, Cyrille and Inderjit, and Genovesi, Piero and Kartesz, John and Morozova, Olga and Nishino, Misako and Nowak, Pauline M. and Pagad, Shyama and Shu, Wen-sheng and Winter, Marten}, title = {Drivers of the relative richness of naturalized and invasive plant species on Earth}, series = {AoB PLANTS}, volume = {11}, journal = {AoB PLANTS}, number = {5}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {2041-2851}, doi = {10.1093/aobpla/plz051}, pages = {13}, year = {2019}, abstract = {Biological invasions are a defining feature of the Anthropocene, but the factors that determine the spatially uneven distribution of alien plant species are still poorly understood. Here, we present the first global analysis of the effects of biogeographic factors, the physical environment and socio-economy on the richness of naturalized and invasive alien plants. We used generalized linear mixed-effects models and variation partitioning to disentangle the relative importance of individual factors, and, more broadly, of biogeography, physical environment and socio-economy. As measures of the magnitude of permanent anthropogenic additions to the regional species pool and of species with negative environmental impacts, we calculated the relative richness of naturalized (= RRN) and invasive (= RRI) alien plant species numbers adjusted for the number of native species in 838 terrestrial regions. Socio-economic factors (per-capita gross domestic product (GDP), population density, proportion of agricultural land) were more important in explaining RRI (similar to 50 \% of the explained variation) than RRN (similar to 40 \%). Warm-temperate and (sub)tropical regions have higher RRN than tropical or cooler regions. We found that socio-economic pressures are more relevant for invasive than for naturalized species richness. The expectation that the southern hemisphere is more invaded than the northern hemisphere was confirmed only for RRN on islands, but not for mainland regions nor for RRI. On average, islands have similar to 6-fold RRN, and >3-fold RRI compared to mainland regions. Eighty-two islands (=26 \% of all islands) harbour more naturalized alien than native plants. Our findings challenge the widely held expectation that socio-economic pressures are more relevant for plant naturalization than for invasive plants. To meet international biodiversity targets and halt the detrimental consequences of plant invasions, it is essential to disrupt the connection between socio-economic development and plant invasions by improving pathway management, early detection and rapid response.}, language = {en} } @article{vanKleunenFischer2003, author = {van Kleunen, Mark and Fischer, Markus}, title = {Effects of four generations of density-dependent selection on life history traits and their plasticity in a clonally propagated plant}, issn = {1010- 061X}, year = {2003}, language = {en} } @article{vanKleunenRamponiSchmid2004, author = {van Kleunen, Mark and Ramponi, G. and Schmid, Bernhard}, title = {Effects of herbivory simulated by clipping and jasmonic acid on growth and reproduction in Solidago canadensis}, year = {2004}, language = {en} } @article{vanKleunenRitland2005, author = {van Kleunen, Mark and Ritland, K.}, title = {Estimating heritabilities and genetic correlations with marker-based methods : an experimental test in Mimulus guttatus}, year = {2005}, abstract = {The calculation of heritabilities and genetic correlations, which are necessary for predicting evolutionary responses, requires knowledge about the relatedness between individuals. This information is often not directly available, especially not for natural populations, but can be inferred by using molecular markers such as allozymes. Several methods based on inferred relatedness from marker data have been developed to estimate heritabilities and genetic correlations in natural populations. Most methods use maximum-likelihood procedures to assign pairs or groups of individuals to predefined discrete relatedness classes (e.g., half sibs and unrelated individuals). The Ritland method, on the other hand, uses method of moments estimators to estimate pairwise relatedness among individuals as continuous values. We tested both the Ritland method and a maximum-likelihood method by applying them to a greenhouse population consisting of seed families of the herb Mimulus guttatus and comparing the results to the ones from a frequently used standard method based on half-sib families. Estimates of genetic correlations were far from accurate, especially when we used the Ritland method. However, this study shows that even with a few variable allozyme loci, it is possible to get qualitatively good indications about the presence of heritable genetic variation from marker-based methods, even though both methods underestimated it}, language = {en} } @article{FischerBurkartPasqualettoetal.2010, author = {Fischer, Markus and Burkart, Michael and Pasqualetto, Vanessa and van Kleunen, Mark}, title = {Experiment meets biogeography : plants of river corridor distribution are not more stress tolerant but benefit less from more benign conditions elsewhere}, issn = {1752-9921}, doi = {10.1093/Jpe/Rtq013}, year = {2010}, abstract = {Aims: Factors limiting distributions of species are fundamental to ecology and evolution but have rarely been addressed experimentally for multiple species. The conspicuous linear distribution patterns of plant species confined to river corridors in the Central European lowlands constitute an especially long-standing distribution puzzle. We experimentally tested our novel hypothesis that the tolerance of species to river corridor conditions is independent of the degree of confinement to river corridor habitats, but that species not confined to river corridors are better able to take advantage of the more benign non-river corridor conditions. Methods: We grew 42 herbaceous species differing in their confinement to river corridors in a common garden experiment on loamy soil typical for river corridor areas and sandy soil typical for non-river corridor areas, and with and without a flooding period. For a subset of species, we grew plants of both river corridor and non-river corridor origin to test for adaptation to river corridor conditions. Important findings: Species more confined to river corridor areas benefited less from the more benign non-flooded and non-river corridor soil conditions than species of wider distributional range did. For subsets of 7 and 12 widespread species, the response to flooding and soil origin, respectively, did not differ between plants from river corridor sites and plants from other sites, suggesting that the habitat tolerance of widespread species is clue to phenotypic plasticity rather than to local adaptation. Overall, we found clear support for our novel hypothesis that species not confined to river corridors are more able to take advantage of the more benign non-river corridor conditions. Our study provides a general hypothesis on differences between species confined to stressful habitats and widespread species out for test in further multispecies comparative experiments.}, language = {en} } @article{FischervanKleunenSchmid2004, author = {Fischer, Markus and van Kleunen, Mark and Schmid, Bernhard}, title = {Experimental life-history evolution: selection on the growth form of a clonal plant on its plasticity}, issn = {1010- 061x}, year = {2004}, abstract = {The growth form along the continuum from compact phalanx plants to more loosely packed guerilla plants is an important life-history trait in clonal plants. Prerequisite for its evolution is heritable genetic variation. Starting with 102 genotypes of the stoloniferous herb Ranunculus reptans, we performed one selection experiment on spatial spread per rosette as measure of guerillaness (broad-sense heritability 0.198) and another on plasticity in this trait in response to competition (broad-sense heritability 0.067). After two generations, spatial spread was 36.9\% higher in the high line than in the low line (realized heritability +/- SE 0.149 +/- 0.039). Moreover, compared with the low line genotypes of the high line had fewer rosettes, a lower proportion of flowering rosettes, a higher proportion of rooted rosettes, more branches per rosette, longer internodes and longer leaves. In the second experiment, we found no significant direct response to selection for high and low plasticity in spatial spread (realized heritability +/- SE - 0.029 +/- 0.063), despite a significant correlated response in plasticity in the length of the first three stolon internodes. Our study indicates a high potential for further evolution of the clonal growth form in R. reptans, but not for its plasticity, and it demonstrates that the clonal growth form does not evolve independently of other clonal life- history characteristics}, language = {en} } @article{vanKleunenDawsonEssletal.2015, author = {van Kleunen, Mark and Dawson, Wayne and Essl, Franz and Pergl, Jan and Winter, Marten and Weber, Ewald and Kreft, Holger and Weigelt, Patrick and Kartesz, John and Nishino, Misako and Antonova, Liubov A. and Barcelona, Julie F. and Cabezas, Francisco J. and Cardenas, Dairon and Cardenas-Toro, Juliana and Castano, Nicolas and Chacon, Eduardo and Chatelain, Cyrille and Ebel, Aleksandr L. and Figueiredo, Estrela and Fuentes, Nicol and Groom, Quentin J. and Henderson, Lesley and Inderjit, and Kupriyanov, Andrey and Masciadri, Silvana and Meerman, Jan and Morozova, Olga and Moser, Dietmar and Nickrent, Daniel L. and Patzelt, Annette and Pelser, Pieter B. and Baptiste, Maria P. and Poopath, Manop and Schulze, Maria and Seebens, Hanno and Shu, Wen-sheng and Thomas, Jacob and Velayos, Mauricio and Wieringa, Jan J. and Pysek, Petr}, title = {Global exchange and accumulation of non-native plants}, series = {Nature : the international weekly journal of science}, volume = {525}, journal = {Nature : the international weekly journal of science}, number = {7567}, publisher = {Nature Publ. Group}, address = {London}, issn = {0028-0836}, doi = {10.1038/nature14910}, pages = {100 -- +}, year = {2015}, abstract = {All around the globe, humans have greatly altered the abiotic and biotic environment with ever-increasing speed. One defining feature of the Anthropocene epoch(1,2) is the erosion of biogeographical barriers by human-mediated dispersal of species into new regions, where they can naturalize and cause ecological, economic and social damage(3). So far, no comprehensive analysis of the global accumulation and exchange of alien plant species between continents has been performed, primarily because of a lack of data. Here we bridge this knowledge gap by using a unique global database on the occurrences of naturalized alien plant species in 481 mainland and 362 island regions. In total, 13,168 plant species, corresponding to 3.9\% of the extant global vascular flora, or approximately the size of the native European flora, have become naturalized somewhere on the globe as a result of human activity. North America has accumulated the largest number of naturalized species, whereas the Pacific Islands show the fastest increase in species numbers with respect to their land area. Continents in the Northern Hemisphere have been the major donors of naturalized alien species to all other continents. Our results quantify for the first time the extent of plant naturalizations worldwide, and illustrate the urgent need for globally integrated efforts to control, manage and understand the spread of alien species.}, language = {en} } @article{SeebensEsslDawsonetal.2015, author = {Seebens, Hanno and Essl, Franz and Dawson, Wayne and Fuentes, Nicol and Moser, Dietmar and Pergl, Jan and Pysek, Petr and van Kleunen, Mark and Weber, Ewald and Winter, Marten and Blasius, Bernd}, title = {Global trade will accelerate plant invasions in emerging economies under climate change}, series = {Global change biology}, volume = {21}, journal = {Global change biology}, number = {11}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1354-1013}, doi = {10.1111/gcb.13021}, pages = {4128 -- 4140}, year = {2015}, abstract = {Trade plays a key role in the spread of alien species and has arguably contributed to the recent enormous acceleration of biological invasions, thus homogenizing biotas worldwide. Combining data on 60-year trends of bilateral trade, as well as on biodiversity and climate, we modeled the global spread of plant species among 147 countries. The model results were compared with a recently compiled unique global data set on numbers of naturalized alien vascular plant species representing the most comprehensive collection of naturalized plant distributions currently available. The model identifies major source regions, introduction routes, and hot spots of plant invasions that agree well with observed naturalized plant numbers. In contrast to common knowledge, we show that the 'imperialist dogma,' stating that Europe has been a net exporter of naturalized plants since colonial times, does not hold for the past 60 years, when more naturalized plants were being imported to than exported from Europe. Our results highlight that the current distribution of naturalized plants is best predicted by socioeconomic activities 20 years ago. We took advantage of the observed time lag and used trade developments until recent times to predict naturalized plant trajectories for the next two decades. This shows that particularly strong increases in naturalized plant numbers are expected in the next 20 years for emerging economies in megadiverse regions. The interaction with predicted future climate change will increase invasions in northern temperate countries and reduce them in tropical and (sub) tropical regions, yet not by enough to cancel out the trade-related increase.}, language = {en} } @article{vanKleunenLenssenFischeretal.2004, author = {van Kleunen, Mark and Lenssen, J. P. M. and Fischer, Markus and de Kroon, H.}, title = {Local adaption of the clonal plant Ranunculus reptans to flooding along a small-scale gradient.}, year = {2004}, language = {en} } @article{EckertHerdenStiftetal.2020, author = {Eckert, Silvia and Herden, Jasmin and Stift, Marc and Joshi, Jasmin Radha and van Kleunen, Mark}, title = {Manipulation of cytosine methylation does not remove latitudinal clines in two invasive goldenrod species in Central Europe}, series = {Molecular ecology}, volume = {30}, journal = {Molecular ecology}, number = {1}, publisher = {Wiley}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.15722}, pages = {222 -- 236}, year = {2020}, abstract = {Invasive species frequently differentiate phenotypically in novel environments within a few generations, often even with limited genetic variation. For the invasive plants Solidago canadensis and S. gigantea, we tested whether such differentiation might have occurred through heritable epigenetic changes in cytosine methylation. In a 2-year common-garden experiment, we grew plants from seeds collected along a latitudinal gradient in their non-native Central European range to test for trait differentiation and whether differentiation disappeared when seeds were treated with the demethylation agent zebularine. Microsatellite markers revealed no population structure along the latitudinal gradient in S. canadensis, but three genetic clusters in S. gigantea. Solidago canadensis showed latitudinal clines in flowering phenology and growth. In S. gigantea, the number of clonal offspring decreased with latitude. Although zebularine had a significant effect on early growth, probably through effects on cytosine methylation, latitudinal clines remained (or even got stronger) in plants raised from seeds treated with zebularine. Thus, our experiment provides no evidence that epigenetic mechanisms by selective cytosine methylation contribute to the observed phenotypic differentiation in invasive goldenrods in Central Europe.}, language = {en} } @misc{EckertHerdenStiftetal.2020, author = {Eckert, Silvia and Herden, Jasmin and Stift, Marc and Joshi, Jasmin Radha and van Kleunen, Mark}, title = {Manipulation of cytosine methylation does not remove latitudinal clines in two invasive goldenrod species in Central Europe}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1}, issn = {1866-8372}, doi = {10.25932/publishup-56952}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-569528}, pages = {17}, year = {2020}, abstract = {Invasive species frequently differentiate phenotypically in novel environments within a few generations, often even with limited genetic variation. For the invasive plants Solidago canadensis and S. gigantea, we tested whether such differentiation might have occurred through heritable epigenetic changes in cytosine methylation. In a 2-year common-garden experiment, we grew plants from seeds collected along a latitudinal gradient in their non-native Central European range to test for trait differentiation and whether differentiation disappeared when seeds were treated with the demethylation agent zebularine. Microsatellite markers revealed no population structure along the latitudinal gradient in S. canadensis, but three genetic clusters in S. gigantea. Solidago canadensis showed latitudinal clines in flowering phenology and growth. In S. gigantea, the number of clonal offspring decreased with latitude. Although zebularine had a significant effect on early growth, probably through effects on cytosine methylation, latitudinal clines remained (or even got stronger) in plants raised from seeds treated with zebularine. Thus, our experiment provides no evidence that epigenetic mechanisms by selective cytosine methylation contribute to the observed phenotypic differentiation in invasive goldenrods in Central Europe.}, language = {en} } @article{DellingerEsslHojsgaardetal.2016, author = {Dellinger, Agnes S. and Essl, Franz and Hojsgaard, Diego and Kirchheimer, Bernhard and Klatt, Simone and Dawson, Wayne and Pergl, Jan and Pysek, Petr and van Kleunen, Mark and Weber, Ewald and Winter, Marten and Hoerandl, Elvira and Dullinger, Stefan}, title = {Niche dynamics of alien species do not differ among sexual and apomictic flowering plants}, series = {New phytologist : international journal of plant science}, volume = {209}, journal = {New phytologist : international journal of plant science}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0028-646X}, doi = {10.1111/nph.13694}, pages = {1313 -- 1323}, year = {2016}, abstract = {We compiled global occurrence data sets of 13 congeneric sexual and apomictic species pairs, and used principal components analysis (PCA) and kernel smoothers to compare changes in climatic niche optima, breadths and unfilling/expansion between native and alien ranges. Niche change metrics were compared between sexual and apomictic species. All 26 species showed changes in niche optima and/or breadth and 14 species significantly expanded their climatic niches. However, we found no effect of the reproductive system on niche dynamics. Instead, species with narrower native niches showed higher rates of niche expansion in the alien ranges. Our results suggest that niche shifts are frequent in plant invasions but evolutionary potential may not be of major importance for such shifts. Niche dynamics rather appear to be driven by changes of the realized niche without adaptive change of the fundamental climatic niche.}, language = {en} } @article{HerdenEckertStiftetal.2019, author = {Herden, Jasmin and Eckert, Silvia and Stift, Marc and Joshi, Jasmin Radha and van Kleunen, Mark}, title = {No evidence for local adaptation and an epigenetic underpinning in native and non-native ruderal plant species in Germany}, series = {Ecology and evolution}, volume = {9}, journal = {Ecology and evolution}, number = {17}, publisher = {Wiley}, address = {Hoboken}, issn = {2045-7758}, doi = {10.1002/ece3.5325}, pages = {9412 -- 9426}, year = {2019}, abstract = {Many invasive species have rapidly adapted to different environments in their new ranges. This is surprising, as colonization is usually associated with reduced genetic variation. Heritable phenotypic variation with an epigenetic basis may explain this paradox. Here, we assessed the contribution of DNA methylation to local adaptation in native and naturalized non-native ruderal plant species in Germany. We reciprocally transplanted offspring from natural populations of seven native and five non-native plant species between the Konstanz region in the south and the Potsdam region in the north of Germany. Before the transplant, half of the seeds were treated with the demethylation agent zebularine. We recorded survival, flowering probability, and biomass production as fitness estimates. Contrary to our expectations, we found little evidence for local adaptation, both among the native and among the non-native plant species. Zebularine treatment had mostly negative effects on overall plant performance, regardless of whether plants were local or not, and regardless of whether they were native or non-native. Synthesis. We conclude that local adaptation, at least at the scale of our study, plays no major role in the success of non-native and native ruderal plants. Consequently, we found no evidence yet for an epigenetic basis of local adaptation.}, language = {en} } @article{vanKleunenRitland2004, author = {van Kleunen, Mark and Ritland, K.}, title = {Predicting evolution of floral traits associated with mating system in a natural plant population}, issn = {1010- 061x}, year = {2004}, abstract = {Evolution of floral traits requires that they are heritable, that they affect fitness, and that they are not constrained by genetic correlations. These prerequisites have only rarely been examined in natural populations. For Mimulus guttatus, we found by using the Riska-method that corolla width, anther length, ovary length and number of red dots on the corolla were heritable in a natural population. Seed production (maternal fitness) was directly positively affected by corolla width and anther size, and indirectly so by ovary length and number of red dots on the corolla. The siring success (paternal fitness), as estimated from allozyme data, was directly negatively affected by anther-stigma separation, and indirectly so by the corolla length-width ratio. Genetic correlations, estimated with the Lynch-method, were positive between floral size measures. We predict that larger flowers with larger reproductive organs, which generally favour outcrossing, will evolve in this natural population of M. guttatus}, language = {en} } @article{LenznerMagallonDawsonetal.2020, author = {Lenzner, Bernd and Magallon, Susana and Dawson, Wayne and Kreft, Holger and K{\"o}nig, Christian and Pergl, Jan and Pysek, Petr and Weigelt, Patrick and van Kleunen, Mark and Winter, Marten and Dullinger, Stefan and Essl, Franz}, title = {Role of diversification rates and evolutionary history as a driver of plant naturalization success}, series = {New phytologist : international journal of plant science}, volume = {229}, journal = {New phytologist : international journal of plant science}, number = {5}, publisher = {Wiley}, address = {Hoboken}, issn = {0028-646X}, doi = {10.1111/nph.17014}, pages = {2998 -- 3008}, year = {2020}, abstract = {Human introductions of species beyond their natural ranges and their subsequent establishment are defining features of global environmental change. However, naturalized plants are not uniformly distributed across phylogenetic lineages, with some families contributing disproportionately more to the global alien species pool than others. Additionally, lineages differ in diversification rates, and high diversification rates have been associated with characteristics that increase species naturalization success. Here, we investigate the role of diversification rates in explaining the naturalization success of angiosperm plant families. We use five global data sets that include native and alien plant species distribution, horticultural use of plants, and a time-calibrated angiosperm phylogeny. Using phylogenetic generalized linear mixed models, we analysed the effect of diversification rate, different geographical range measures, and horticultural use on the naturalization success of plant families. We show that a family's naturalization success is positively associated with its evolutionary history, native range size, and economic use. Investigating interactive effects of these predictors shows that native range size and geographic distribution additionally affect naturalization success. High diversification rates and large ranges increase naturalization success, especially of temperate families. We suggest this may result from lower ecological specialization in temperate families with large ranges, compared with tropical families with smaller ranges.}, language = {en} } @misc{LenznerMagallonDawsonetal.2020, author = {Lenzner, Bernd and Magallon, Susana and Dawson, Wayne and Kreft, Holger and K{\"o}nig, Christian and Pergl, Jan and Pysek, Petr and Weigelt, Patrick and van Kleunen, Mark and Winter, Marten and Dullinger, Stefan and Essl, Franz}, title = {Role of diversification rates and evolutionary history as a driver of plant naturalization success}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {5}, issn = {1866-8372}, doi = {10.25932/publishup-56999}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-569996}, pages = {13}, year = {2020}, abstract = {Human introductions of species beyond their natural ranges and their subsequent establishment are defining features of global environmental change. However, naturalized plants are not uniformly distributed across phylogenetic lineages, with some families contributing disproportionately more to the global alien species pool than others. Additionally, lineages differ in diversification rates, and high diversification rates have been associated with characteristics that increase species naturalization success. Here, we investigate the role of diversification rates in explaining the naturalization success of angiosperm plant families. We use five global data sets that include native and alien plant species distribution, horticultural use of plants, and a time-calibrated angiosperm phylogeny. Using phylogenetic generalized linear mixed models, we analysed the effect of diversification rate, different geographical range measures, and horticultural use on the naturalization success of plant families. We show that a family's naturalization success is positively associated with its evolutionary history, native range size, and economic use. Investigating interactive effects of these predictors shows that native range size and geographic distribution additionally affect naturalization success. High diversification rates and large ranges increase naturalization success, especially of temperate families. We suggest this may result from lower ecological specialization in temperate families with large ranges, compared with tropical families with smaller ranges.}, language = {en} } @article{vanKleunenJohnson2005, author = {van Kleunen, Mark and Johnson, S. D.}, title = {Testing for ecological and genetic Allee effects in the invasive shrub Senna didymobotrya (Fabaceae)}, year = {2005}, abstract = {For an introduced plant species to become invasive, it must be able to reproduce even in initially small populations We tested for Aliee effects (reduced reproductive performance of individuals in small populations) in the nonclonal, NW-pollinated shrub Senna didymobotrya in its invasive range in South Africa. The species is self-compatible. but we found that in its invasive range in South Africa it requires pollinators to set seed. Nearly all stigmas (90\%) received pollen. but natural fruit set has very low (3-20\%), Pollen receipt and fruit set were not significantly correlated with population size. We thus found no evidence for an ecological Alice effect arising from pollen limitation in small populations. Offspring seedling performance, measured in terms of stern volume and leaf area, was also not significantly correlated with the number of plants in the source population. indicating that genetic Alice effects, such as inbreeding depression, are either absent or of such a small magnitude that they would be unlikely to limit further spread of S. didymobotrya in South Africa}, language = {en} } @article{vanKleunenEsslPergletal.2018, author = {van Kleunen, Mark and Essl, Franz and Pergl, Jan and Brundu, Giuseppe and Carboni, Marta and Dullinger, Stefan and Early, Regan and Gonzalez-Moreno, Pablo and Groom, Quentin J. M. and Hulme, Philip E. and Kueffer, Christoph and K{\"u}hn, Ingolf and Maguas, Cristina and Maurel, Noelie and Novoa, Ana and Parepa, Madalin and Pysek, Petr and Seebens, Hanno and Tanner, Rob and Touza, Julia and Verbrugge, Laura and Weber, Ewald and Dawson, Wayne and Kreft, Holger and Weigelt, Patrick and Winter, Marten and Klonner, Guenther and Talluto, Matthew V. and Dehnen-Schmutz, Katharina}, title = {The changing role of ornamental horticulture in alien plant invasions}, series = {Biological reviews}, volume = {93}, journal = {Biological reviews}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {1464-7931}, doi = {10.1111/brv.12402}, pages = {1421 -- 1437}, year = {2018}, abstract = {The number of alien plants escaping from cultivation into native ecosystems is increasing steadily. We provide an overview of the historical, contemporary and potential future roles of ornamental horticulture in plant invasions. We show that currently at least 75\% and 93\% of the global naturalised alien flora is grown in domestic and botanical gardens, respectively. Species grown in gardens also have a larger naturalised range than those that are not. After the Middle Ages, particularly in the 18th and 19th centuries, a global trade network in plants emerged. Since then, cultivated alien species also started to appear in the wild more frequently than non-cultivated aliens globally, particularly during the 19th century. Horticulture still plays a prominent role in current plant introduction, and the monetary value of live-plant imports in different parts of the world is steadily increasing. Historically, botanical gardens - an important component of horticulture - played a major role in displaying, cultivating and distributing new plant discoveries. While the role of botanical gardens in the horticultural supply chain has declined, they are still a significant link, with one-third of institutions involved in retail-plant sales and horticultural research. However, botanical gardens have also become more dependent on commercial nurseries as plant sources, particularly in North America. Plants selected for ornamental purposes are not a random selection of the global flora, and some of the plant characteristics promoted through horticulture, such as fast growth, also promote invasion. Efforts to breed non-invasive plant cultivars are still rare. Socio-economical, technological, and environmental changes will lead to novel patterns of plant introductions and invasion opportunities for the species that are already cultivated. We describe the role that horticulture could play in mediating these changes. We identify current research challenges, and call for more research efforts on the past and current role of horticulture in plant invasions. This is required to develop science-based regulatory frameworks to prevent further plant invasions.}, language = {en} } @article{vanKleunenFischerSchmid2005, author = {van Kleunen, Mark and Fischer, Markus and Schmid, Bernhard}, title = {Three generations under low versus high neighborhood density affect the life history of a clonal plant through differential selection and genetic drift}, year = {2005}, abstract = {We tested whether neighborhood density affects the clonal life history of the stoloniferous plant Ranunculus reptans through selection and genetic drift. After three generations of sexual reproduction of 16 low- and 16 high- density lines, we studied traits related to growth form and reproduction in a common competition free environment. A 7.7\% lower branching frequency and slightly longer internodes indicated an evolutionary shift towards a less compact growth form under high neighborhood density, but because stolons grew also more vertically, horizontal spread per ramet was slightly decreased. Neighborhood density had no directional effects on the evolution of allocation to sexual and vegetative reproduction in R. reptans. Variation among replicated high-density lines was significantly lower than among replicated low-density lines in both growth form and reproductive characteristics, indicating less pronounced genetic drift under high neighborhood density. This study demonstrates that a clonal plant can respond to selection imposed by neighborhood density. Moreover, it shows that the effect of random genetic drift increases with decreasing neighborhood density. In a declining species, such as R. reptans in central Europe, this may lower the potential for adaptive evolutionary change and increase extinction risk}, language = {en} }